Incandescent electric lamp



Dec. 20, 1927. 1,653,365

C. F. LORENZ INCANDESCENT ELECTRIC LAMP Filed June 28. 1923 INVENTOR CHARLE'SELORENZ ATTORNEY Patented Dec. 20, 1927.

UNITED- STATES PATENT OFFICE.

CHARLES FREDERICK LORENZ, OFEAST ORANGE, NEW JERSEY, ASSIGNOR TC WEST- INGHOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

, INCANDESCENT ELECTRIC LAMP.

Application filed June 28, 1923. Serial No. 648,186.

This invention pertains to electric lamps in general and more particularly to electric lamps having a radiant, suitable for projection purposes.

It is an object of the invention to provide an. efficient electric lamp by so arranging the incandescible element thereof that it will have a massive form as distinguished from a filamentary form.

It is another object to provide anincandescent element for an electric lamp by which a concentrated light source may be obtained.

It is another object to provide an electric lamp having a concentrated light source by a peculiar association of electrodes and a resistor element.

Another object is to reduce to a minimum the blackening of the bulb of the lamp, from wolatilization of the light-giving body, thereby increasing the life of the lamp and its illuminating efficiency.

A further object is to devise an incandescible body that will have a long commercial life.

Other objects are apparent or will become apparent from thedescription, claims and drawing in which Fig. 1 is an elevation, partly in section, of a preferred form of the invention;

- Fig. 2 is a modification thereof; and,

Fig. 3 is a sectional View taken on the line IIIIII of Fig. 2.

Fig. 4t isv a sectional View taken on line 1V-1V of Fi 1.

In a copending application, Serial No. 624,915, filed March let, 1923, entitled Luminous electrode discharge lamp and assigned. to the \Vestinghouse Lamp Company, I have disclosed a lamp having two metallic bodies or electrodes, positioned one within the other, with a gaseous path between the two and in another copending application Serial No. 648,187 filed June 28, 1923,.entitled Arc incandescent lamp with special electrodes, I have disclosed a pair of incandescible composite bodies as are electrodes, whereas, in the invention here described, I provide a highly refractory material, hav ing suitable electrical resistance between substantially concentric members of an incandeseible body. This material may be a mixture of thoria and tungsten, the tungsten being added for electrical conductivity. The refractory mixture retains the heat generated and as the incandescible body is compactin this arrangement, it provides a restricted or concentrated source of light. Many other advantages accrue, such as reduction in blackening of the glass globe from volatilized metal, as a large part of all volatile matter will be trapped within the interior walls of the outer member of the incandescible body or in the refractory material between the outer andv inner members thereof.

In addition to the features set forth, supra, a tube or'other suitable means may be provided to trap metallic or other vapors, generated within the outer member of the incandescible body or between the inner and outer members thereof, to prevent such vapors from reaching the surface of the bulb or enclosing apparatus. By such means, the gases or vapors generated Within the outer member are confined to a s )ace which ensures their retention and freedom of the bulb from any objectionable action they might have. The tube may, in addition, act as a conductor for one of the incandescible members and this type of construction constitutes .a preferred, form. Hereinafter, for

1 convenience, I shall refer to the inner and outer members .of the incandescible body as electrodes. i

In Fig. 1 is shown the preferred type of the invention and wherein an electrode 2, which may be of tungsten in the shape of a hollow sphere, is provided with an opening 4 to permit insertion of a corresponding electrode 6 therein. The electrode 6 may also be composed of tungsten or a similar metal and its exterior surface substantially conforms to the inner surface of the electrode 2 to render the two electrodes substantially concentric, to prevent unequal heating of the incandescible member. Between the electrodes 2 and 6, is a refractory material 8, to act as a heating and heat retaining element. The material 8 should be highly refractory for heating to incandescence and for this purpose a mixture" or agglomerate of tungsten powder with thoria, boron or silicon nitride may be used, but other material having the necessary qualifications may be substituted. The refractory mass 8 may be agglomerated in any suitable proportions or mannerand tightly or loosely compacted between the substantially concentrio electrodes, as desired. WVith a light (ill source composed of a tungsten sphere of approximately one centimeter in diameter and an inner metallic body of about one half centimeter in diameter, it is necessary, in order to maintain the outer shell at a temperature of about 3000 C. absolute, with a potential of 110 volts, that the refractory resistance material 8 have a specific resistance of about 80. I prefer to use a mixture of tungsten and thoria in order to obtain a composition of the proper specific resistance but no definite proportions of such mixture can be stated since they differ radically with the particle size of the powdered ingredients and the degree of compactness thereof. ith the particular materialsavailable, however, a few simple trials will sufiice to enable those skilled in the art to produce a inixture having a specific resistance of aboutSQ, The filling may be done by packing the dry powder in place under suitable pressure. To avoidloss of the material 8, in case it may be loosely packed between the electrodes, the surface 10 thereof may be hardened by compression and such surface portion should have a larger percentage of the insulating ingredient in order that the resistance of this compact portion will be equal to or greater than the body portion of the refractory mass 8 In the type of lamp illustrated in Fig. 1, the electrode 2 is shown in the shape of a hollow sphere with a conical flange 12, which may be of the same material as the sphere, welded or otherwise secured to a tube 1% of molybdenum, secured in turn in any suitablemanner to a tube of steel 16, in turn secured to a copperseal 18 for connection to one side of the source of power. The electrode 6 comprises a stem 20 of tungsten or like material, welded or otherwise secured at 22 to a molybdenum lead 22 which is electrically connected to the base or plug member 24 for connection to the op posite side of a source of power.

It will be noted that with the construction of Fig. 1 as described, the electrodes are rigid and immovable with respect to each other and. by constriiicting the outer lead, generally designated 26, in tube form the vapors formed in the interior of the electrode 2 cannot blacken or otherwise injure the glass 28 of the enclosing bulb. In Figures 2 and 3, I have shown an alternative form of construction of the outer electrode support, whereby a plurality of supporting leads 30 are connected between the outer shell 2 and one side of a source of electricity while the usual interior lead 26 is connected to the other side. The space between the inner and outer electrodes 6 and 2 is filled with a refractory material 8 of higher resistance than said electrodes, as described in connection with F 1 for heating the outer electrode 2 to incandescence. The lamp may be evacuated or filled with a gas inert with respect to the electrodes under any desirable pressure, while the leads 2?, 26 and may be sealed in, in any appropriate manner.

The operation of the types of lamp shown in Figures 1, and 33 is as follows. Upon connection to either a l). C. or an A. C. source of suiiicicnt potential, the current passes from one electrode to the other through the mass 8 heating the refractory mass 8 because of its resistance. This heating continues until the elcctrodts and material 8 become incandescent, the light therefron'i radiating in practically all directions and giving a 'cstrictcd and cmicentraieil source of light, while the loss of heat through the gas within the lamp will be small comifiarcd with that from a lilamcnt at the same ten'lperature and having the same surface area. The life of this type of lamp will be long compared with that of a filament lamp operating at the same tcmperatiire.

While I have illustrated and described a particular and what I consider to be the preferable form of my invention, it will be apparent that may departures may be made therefrom without departing from the spirit and scope of the invention.

IV hat is clain led is:

1. An incandescent lamp comprising a hollow substantially spherical refractory body and an electrical heater comprising an electrode concentrically disposed therein in intimate contact therewith for heating said body by conduction.

2. An incandescent lamp centrated light source adapted for projee tion purposes coniprisIng a sealed envelope and an incandescible body therein composed of two concentric. spherical metallic elements having current conductors connected thereto and a refractory heating medium between said elements in physical contact therewith for heating one of said bodies to incandcscence.

3. An incandescent lamp comprising an ei'welope, a light l-hTrlltt therein, comprising a pair of concentric comlucting elen'ients hating a refractory heating material there between for heating one o't said conducting elements, said element constituting the entire light som'ce of said, lamp. 7

4:. In an electric lamp, an incandescible body coi'nprising' a plurality of sul'istantially concentric spherical electrodes and a highly refractory heating compound therebetwecn.

5. In an electric lamp, an incandescible body comprising, substantially concentric spherical electrodes of metal having a highly refractory material thcrehctween. I

6. An incandescent lamp comprising a sealed envelope and an incandesciliile body therein, said body comprising a hollow spherical metal electrode, a second spherical having a con.-

iii!

electrode concentric therewith and a body of highly refractory material between said electrodes.

7. An incandescent lamp having a concentrated light source comprising a refractory metal container, a high resistance therein,

and means for passing electric currents through said resistance material to heat the same and thereby render the container incandescent.

S. An incandescent lamp having a concentrated light source comprising a metallic container, a high resistance material contained therein, a current conductor connectec thereto and a second current conductor surmimding said container and in con tact with said high resistance material whereby current may be passed there- 'hrough.

a. fin incandescent lamp comprising an envelope, a light source therein comprising a refractory metal shell, a backing of high resistance material therein and means for passing current through said refractory ma terial to heat the same and thereby render the shell incandescent.

10. An incandescent lamp comprising an envelope, a hollow refractory shell therein, a refractory body Within said shell spaced in equal distance from the Walls thereof, a r

high resistance material between said shell and body and means for passing current through said material to heat the same and thereby render said shell incandescent.

11. An incandescent lamp comprising a hollow refractory shell containing a material having higher electric resistance than said shell, an electrical conductor connected to said shell and a conductor within said material causing a current to pass uniformly theretln'ough to heat the same and thereby render said shell incandescent.

In testimony whereof, I have hereunto subscribed my name this 26th day of June, 1923.

CHARLES FREDERICK LORENZ. 

